1. Any Statement in a proposal or a specification such as "As needed" or "As required" begs the question "as needed in who's opinion" or "As required by whom" You will not find this type of verbiage in any specification written by me.
2. Unit prices for unforseen work must be defined. In other words the size of replacement sheathing must be delineated, and is usually minimum 4 x 4, and it must bear on three supports (Rafters) The word Provide, in CSI language means properly installed and includes all materials, labor, overhead and profit.
There must be a breakdown on quantity, ie 1-400 sq ft 400-1000 sq ft etc. and the right to re-negotiate at cost plus should all of the sheathing need to be replaced.
3. The use of the pound sign after the type of felt is a dead giveaway of ignorance. No. 30 Felt is not 30 lbs. per square, nor is No. 15 felt 15 lbs. per square. You do NOT want ASTM 226 Type 2 (No. 30) felt under asphalt shingles. If it gets wet, it will buckle and transmit through the shingles leaving an unsightly roof. ASTM D226 Type 1 (No. 15) is good felt for use under shingles, but keep it dry, and install just ahead of shingles. Use the best underlayment warranted by the shingle mfgr.
4. Ice dams material should be used in valleys, rakes and at eaves. Metal should be aluminum, not galvanized steel, and should be enveloped at the eaves by installing a 12 inch strip of ice dams material under the flange, nailing the flange at about 16 inches on center, and running a full sheet over the nailed flange.
5. I don't like metal in the valleys with asphalt shingles with the advent of ice dams material. I like closed cut valleys over double ice dams. Metal moves too much in relation to Bituminous materials and people tend to nail through the valley metal. Bad news. I will hear flak on this but I don't give a crap. If the sheathing is bad at the valleys, the valley can be lined under all with metal for support of the ice dams, but that's about it.
6 How sheathing is nailed must be defined. Please refer to APA. 8d galv ring shank nails 6 inches O.C. Edges and 12 inches O.C intermediate. Resin coated galv in pneumatic guns is likely and fine.
Read the proposals closely. A new roof should include all new accessories including new roof jacks, New seamless gutters and downspouts with hidden hangers 24 inches on center in the gutters, and cleaning of the fascia metal and the ventilated soffits. Replacement of fascia cladding is usually a good idea, because the old one is going to be mouldy, and have holes where you dont want them. Replacement allows removal and cleaning of the Soffit Material.
A new roof should be a comprehensive look at the upper building envelope system, not just the shingles. Without a good specification, the roofers are looking for a way to do the job for less than the next guy, and you will be the loser. If you give them a good spec to bid on you get apples to apples. If you are ignorant, you are getting apples, oranges, and probably LEMONS.
Hope some of this helps.
JA
